When performing production testing of mobile devices, for example mobile telephones, a great number of devices under test have to be processed. In recent years, increasing integration of the necessary testing equipment is a significant trend. Especially the use of integrated signal generators for providing measuring signals to several independently measured devices under test has led to new problems.
So far, a synchronization of the individual signal generators within one measuring device has not been attempted. Interference between the different signal generators within the measuring device is so far present, since for example on a first measuring path, a high amplitude signal is generated, while on a second measuring path, a low amplitude signal is generated. Due to the close spatial proximity of the individual signal generators within the measuring device, the high amplitude signal at least in part couples onto the low amplitude signal measuring path and negatively influences this measuring path. This results in a higher than necessary number of devices under test being discarded due to not meeting the desired specifications.
For example, the U.S. Pat. No. 7,772,928 B2 shows a measuring system performing a synchronization of several signal generators by use of the master-slave principle. The system shown there though is very complex, since an exact phase synchronization is performed. Moreover, the system shown there only permits the different signal generators to work in perfect union. This means that the signal generators have to start sending their respective measuring signals at exactly the same time. This results in a reduced flexibility of use.
Accordingly, one object of the invention among others is to provide a measuring system and a measuring method, which allow for performing measurements on several devices under test parallel but independently while at the same time preventing interference between the different signal generators.